Clinically Useful Predictors of Resistance to Intravenous Immunoglobulin and Prognosis of Coronary Artery Lesions in Patients with Incomplete Kawasaki Disease

Background and Objectives: The prevalence of incomplete Kawasaki disease (iKD) is progressively increasing. We aimed to retrospectively investigate the predictors of intravenous immunoglobulin (IVIG) resistance in iKD patients and compare them with those of IVIG resistance in complete Kawasaki disease (cKD) patients. We also compared the prognosis of coronary artery lesions (CALs) between the IVIG non-responders and responders in both iKD and cKD groups.S ubjects and Methods: A total of 234 cKD and 77 iKD patients were treated with IVIG between February 2009 and April 2012. Among these 311 patients, we reviewed the data of 77 iKD patients and 75 age-matched cKD patients. Results: Patients with iKD having an elevated neutrophil count {percentage of segmented neutrophils (SEG%) ${\geq}79.0$} were at risk of IVIG resistance, while patients with cKD having SEG% ${\geq}79.25$ and serum total bilirubin (TB) ${\geq}0.56mg/dL$ were at risk of IVIG resistance as shown by multivariable logistic regression analysis. Fractional changes of laboratory data before and after IVIG treatment showed that Creactive protein (CRP) and N-terminal B type natriuretic peptide (NT-proBNP) levels were significantly elevated in IVIG non-responders of the iKD group, whereas erythrocyte sedimentation rate was significantly elevated in IVIG non-responders of the cKD group. Among the patients who had CALs at 10 months after the start of illness, the z scores of coronary arteries were higher in IVIG non-responders of the iKD group, when compared with IVIG non-responders of the cKD group. Conclusion: Elevated SEG%, changes in CRP and NT-proBNP levels may help in early detection of IVIG resistance in patients of the iKD group, which may aid in predicting the prognosis of CALs in these patients. Further studies with a larger number of patients are warranted.